I argue for the thesis (UL) that there are certain logical abilities that any rational creature must have. Opposition to UL comes from naturalized epistemologists who hold that it is a purely empirical question which logical abilities a rational creature has. I provide arguments that any creatures meeting certain conditions - plausible necessary conditions on rationality - must have certain specific logical concepts and be able to use them in certain specific ways. For example, I argue that any creature able to grasp theories must have a concept of conjunction subject to the usual introduction and elimination rules. I also deal with disjunction, conditionality and negation. These cases are not intended to be exhaustive of universal logical abilities. Finally, I put UL to work in showing how it could be used to define a notion of logical obviousness that would be well suited to certain contexts - e.g. radical translation and epistemic logic - in which a concept of obviousness is often invoked.